On Sat, 29 Jun 2024 17:41:47 GMT, David Schlosnagle <d...@openjdk.org> wrote:
>> src/java.base/share/classes/java/lang/StringFormat.java line 82:
>>
>>> 80: conv = format.charAt(off + 2);
>>> 81: }
>>> 82: }
>>
>> is it worth handling `width > 9`?
>>
>> Suggestion:
>>
>> for (int i = 2; conv >= '1' && conv <= '9' && off + i < max; i++) {
>> width = (width * 10) + (conv - '0');
>> if (off + i < max) {
>> conv = format.charAt(off + i);
>> }
>> }
>
> a quick local benchmark on 2021 MacBook M1 Pro before/after motivating this:
>
>
> @Benchmark
> public String wideStringIntFormat() {
> return "%123s %42d".formatted(s, i);
> }
>
>
> #### Before:
>
> Benchmark Mode Cnt Score Error Units
> StringFormat.wideStringIntFormat avgt 15 377.603 ± 85.742 ns/op
>
>
> #### After:
>
> Benchmark Mode Cnt Score Error Units
> StringFormat.wideStringIntFormat avgt 15 54.104 ± 0.079 ns/op
But this is a fastpath optimization, is width > 9 common enough?
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PR Review Comment: https://git.openjdk.org/jdk/pull/19956#discussion_r1659951995
